Granulator with noise abatement and safety means

ABSTRACT

A device for comminuting or granulating plastic and like material including a housing having a rotating cutter therein, at least one fixed cutter cooperating with the rotating cutter, and a perforated screen, insulated mounting means mounting the fixed cutter and screen in fixed but insulated relationship with respect to the housing thereby greatly abating noises. The device also has access means for supplying materials to be comminuted including an access opening remote from the rotating cutter by a distance greater than the reach of an operator thereby preventing operator contact with the rotating cutter. The device has removable parts which provide access to the rotating cutter and there are control means for the rotating cutter for rendering the rotating cutter inoperative upon the removal of any one of the removable parts.

United States Patent Shah 1 1 July 29, 1975 1 1 GRANULATOR WITl-ll NOISEABATEMENT 3,785,579 1/1974 Voglesonger 241/2821 AND SAFETY MEANS3,790,093 2/1974 McIntyre 241/73 [75] Inventor: Sunil Chunilal Shah,Cranston, RI.

[73] Assignee: Cumberland Engineering Company,

lnc., South Attleboro, Mass.

[22] Filed: Mar. 27, 1974 [21] Appl. No.: 455,125

[52] US Cl. 241/73; 83/349; 83/658; 83/700; 241/100; 241/101.7; 241/224;241/285 A [51] Int. Cl. B02C 18/06; BOZC 18/44 [58] Field of Search..24l/73,100,101.7, 189 R, 241/222, 224, 282.1, 285R, 285 A, 285 B;83/349, 658, 700

{56] References Cited UNITED STATES PATENTS 2,890,840 6/1959 Fletcher cta1 241/73 3,419,223 12/1968 Morin 241/73 3,612,126 10/1971 Emmons etal..... 41/2821 X 3,756,519 9/1973 Reynolds ct al. 241/100 X 3.763.74810/1973 Gallagher 83/658 X 3,769,868 11/1973 Strucker 83/349 PrimaryExaminer-Granville Y. Custer, Jr.

Ass/slam Examiner-Howard N. Goldberg Attorney, Agent, or Firm-Albert P.Davis; Burnett W. Norton [5 7] ABSTRACT A device for comminuting orgranulating plastic and like material including a housing having arotating cutter therein, at least one fixed cutter cooperating with therotating cutter, and a perforated screen, insulated mounting meansmounting the fixed cutter and screen in fixed but insulated relationshipwith respect to the housing thereby greatly abating noises. The devicealso has access means for supplying materials to be comminuted includingan access opening remote from the rotating cutter by a distance greaterthan the reach of an operator thereby preventing operator contact withthe rotating cutter. The device has removable parts which provide accessto the rotating cutter and there are control means for the rotatingcutter for rendering the rotating cutter inoperative upon the removal ofany one of the removable parts.

7 Claims, 6 Drawing Figures PATENTEB JUL 2 9 I975 SHEET PATEm nJuLzslszsSHEET may GRANULATOR WITH NOISE ABATEMENT AND SAFETY MEANS Thisinvention relates in general to new and useful improvements incomminuting or granulating devices, and more particularly to agranulating device having cooperative rotating and fixed cutters.

BACKGROUND OF THE INVENTION Granulators for comminuting plastics andlike material utilizing cooperating rotating and fixed cutters andassociated material sizing screens are known noise pollutors and may notmeet the noise pollution standards imposed by modern industrial laws.

Certain granulators may also fail to meet safety requirements in that itmay be possible for an operator, working under abnormal conditions, toinadvertently place his hand into contact with the rotating cutter.Further, certain granulators are constructed wherein certain partsthereof, such as entry chutes, side panels, etc., may be removed withoutthe drive for the rotating cutter being disabled.

SUMMARY OF THE INVENTION The most common expedient way in combatingnoise pollution is to enclose noise-polluting machinery with insulatedhousings. While such housings do successfully reduce noise the initialcost of the noise-abating housing increases the over-all cost ofgranulators and access to the machinery is restricted when repairs orinspections of the granulator are required.

In accordance with this invention, it is proposed to construct agranulator wherein critical elements thereof have insulated mountings,the construction of which is such that noises which might be producedduring normal interaction of a rotating cutter with a fixed cutter aresubstantially eliminated. Further, the screens associated with thecutter elements are also mounted in an insulated manner so as to greatlyreduce noise transfer. The net result of such insulated mountings andother features of the invention'is to produce a granulator whichsubstantially reduces noise pollution without requiring complex andexpensive insulated housings.

Another feature of this invention is that the required insulation of thegranulator may be accomplished by the simple use of the fasteners havingresilient mounting components which effectively absorb noise, shock, andvibration even under high-impact conditions.

Another feature of this invention is the provision of a feed hopperhaving an access opening which is spaced from the path of the rotatingcutter a distance in excess of the reach of an operator whereby it isphysically impossible for the operator to reach the path of the rotatingcutter even under the most abnormal conditions.

Another feature of the invention is the provision of a feed hopperhaving a feed muffer with a unique drawtype inner assembly with flexiblebaffles therein which simultaneously serves to deflect material placedin the granulator into the path of the rotating cutter and to preventchips of material flung by the rotating cutter from ricocheting outthrough the access opening while attenuating airborne noise that wouldotherwise normally escape through the feed opening.

A further feature of the invention is the provision of switch means forrendering inoperative the drive for the rotating cutter when the feedhopper or certain parts of the removable panels of the housing'of thegranulator are removed, whereby it is impossible to ef feet the drivenrotation of the rotating cutters when access to the path thereof isobtainable.

Another feature of this invention is the integrated design wherebyvarious sections normally found in conventional granulators such as thebase, cutting section and feed chute are integrated into one piece withsuitable access doors, thereby minimizing the leakages of noise fromwhere the conventional sections normally abut against each other.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims, and theseveral views illustrated in the accompanying drawings.

FIG. 1 is a front elevational view of the granulator with parts brokenaway and shown in section;

FIG. 2 is a side elevational view of the granulator and shows generallythe details of the feed hopper in the relationship thereof with respectto the rotating cutter;

FIG. 3 is a view taken along the lines 3-3 of FIG. 1 showing in detailthe means for rendering the drive for the rotating cutter inoperativeupon the removal of components of the granulator;

FIG. 4 is an enlarged fragmentary vertical sectional view taken alongthe line 44 of FIG. 1 and shows the details of the rotating cutter, thefixed cutters associated therewith, the sectional screen associatedtherewith, and mountings of the fixed cutters and sectional screen;

FIG. 5 is an enlarged fragmentary sectional view taken along the line5--5 of FIG. 1 and shows further the details of an insulated support forthe lower fixed cutter, and for adjacent portions of the sectionalscreen; and

FIG. 6 is an enlarged fragmentary sectional view taken along the line 66of FIG. 1 and shows the adjustable mounting of the lower fixed cutterand the lower edge of the front screen section.

Referring now to the drawings in detail, it will be seen that thegranulator is generally identified by the numeral l0 and includes rigidbase 11 having two opposite sides thereof reinforced by a pair ofchannel members 12 secured to the underside thereof. The front end ofthe base is provided with a pair of fixed support wheels 13 while therear end of the base 11 is provided with a pair of casters 14.

Seated on base 11 and extending upwardly therefrom is a generallyrectangular housing 15. Housing 15 includes a pair of thick and veryrigid side plates 16 and 17 which are suitably secured to base 11 infixed relationship. Extending between side plates 16, 17 at the frontedges thereof and removably secured thereto by a plurality of fasteners18 is a front panel or door 20. A similar rear panel or door 21 issecured to rear edges of the side plates by means of like removablefasteners 22. Doors 20, 21 provide access to the interior of housing 15for adjustment and mounting of the cutting knives positioned withinhousing 15. Doors 20 and 21 are laminates consisting of opposite outersteel plates between which is sandwiched] a layer of visco-elasticplastic to minimize the generation of noise by these members.

Referring now to FIGS. 1 and 4, it will be seen that side plates 16, 17carry bearing assemblies 23, 24, respectively, for the shaft ends 25,26, respectively, of a two knife, hollow rotor 27. Shaft end 26 has aflywheel sheave 28 mounted thereon. Rotor 27 has removably mountedthereon a pair of rotor knives 30 which are secured in place by means offasteners 31.

A knife holding block 32 extends between the side plates or panels 16,17 adjacent front panel or door and has the opposite ends thereoffixedly secured to side panels 16, 17 in a conventional manner. A bedknife 33 is adjustably clamped to knife holding block 32 by means of anupstroke knife shield 34 which is secured in place by suitable fasteners35 which pass through openings 36 in bed knife 33 and which are threadedinto knife holding block 32.

Bed knife 33 is adjusted by means of a set screw 37. It is to beunderstood that the position of bed knife 33 is adjusted so as tocooperate with rotating rotor blades or knives 30.

Also extending between and fixedly secured to side panels 16, 17 is asupport block 38. Support block 38 has removably secured along the frontedge thereof by means of fasteners 40 a front clamp block 41. A similarrear clamp block 42 is removably secured along the rear edge of supportblock 38 by means of fasteners 43. It is to be noted that clamp block 42is chamfered at 42a (see FIG. 5) for guiding the movement of knifeholding block 44 next to be described. Support block 38 and clamp blocks41 and 42 combined to define a generally outwardly opening channelshaped support.

A downstroke knife holding block 44 is supported by the support block 38in insulated relation. Block 44 is of a generally inverted T-shapedoutline and has the cross-bar portion thereof in overlying relation tosupport block 38 and within the confines of the recess defined by clampblocks 41 and 42.

Block 44 is provided with a plurality of bores 45 on the undersidethereof and fitted in each bore 45 is a shouldered resilient inserthaving an internal nut 47 bonded thereto. Each shouldered insert 46 alsoincludes at one end thereof a shoulder 48 which abuts against the undersurface of block 44.

Suitable fasteners 50 extend through the support block 38 and arethreaded into nut insert 47. Fasteners 50 simultaneously effectexpansion of the shoulder inserts so as to clamp the same within bores45 and draw block 44 towards support block 38 so as to compress shoulder48. In this manner, block 44 is resiliently mounted on support 38 ininsulated relation.

It is to be understood that fasteners 50 draw block 44 down towardsupport block 38 only sufficiently to permit clamp blocks 41, 42 toengage over the projecting edges of block 44, as is shown in FIG. 5.

Referring now to FIG. 5, it will be seen that knife holding block 44 isfurther secured to support block 38 in insulated relation by a pluralityof special resiliently mounted fasteners identified by the numeral 51.Each fastener 51 includes a resilient body 52 having extending from oneend thereof a first threaded portion 53 and from the opposite endthereof a second threaded portion 54. The threaded portion 53 isthreadedly engaged in a bore in block 44 with body 52 in an abuttingengagement therewith. Body 52 is seated in a suitable bore 55 in therespective one of clamp blocks 41, 42 and the opposite threaded stud 54extends through a bore in the clamp block and is tightened in place bymeans of a nut 56.

It is to be understood that fasteners 51 are positioned on knife holdingblock 44 and thereafter clamp block 41, 42 are engaged thereover. Nuts56 are then applied so as to draw clamp blocks 41, 42 into positionwherein fasteners 40, 43, respectively, securing the clamp blocks tosupport block 38, are aligned with the respective bores in support block38 for the fasteners. Fasteners 40, 43 are then applied so as to drawclamp blocks 41, 42 tightly against support block 38. It is to be notedthat chamfer 42a guides the movement of knife holding block 44 topreclude interference between rotor knives 30 and bed knife 57. It willnow be apparent that at this time the knife holding block 44 is mountedwith respect to the support block 38 in insulated relation such as topermit only such movements of knife holding block 44 that will notresult in interference between the rotating knives 30 and bed knife 57and, also, that will not change the relationship between rotating knives30 and bed knife 57 beyond ordinary permissible limits during operationof the granulator.

As is clearly shown in FIGS. 4, 5 and 6, a lower bed knife 57 is clampedto knife holding block 44 by means of suitable fasteners 58. Saidfasteners 58 engage a clamp block 60 and extend therethrough to passthrough enlarged openings 61 in bed knife 57. Fasteners 58 also passthrough an upstroke knife shield 62 and are also engaged in knifeholding block 44. As is best illustrated in FIG. 6, knife shield 62 andbed knife 57 are adjustable relative to knife holding block 44 by meansof set screws 63 and 64, respectively, which are threaded in threadedbores of knife holding block 44.

Access openings 65 and 66 are formed, in support block 38 to facilitateadjustment of set screws 63, 64, respectively.

Viewing FIGS. 4, 5 and 6, there is mounted within housing 15 a sectionalperforated screen which includes a front screen section 67. The frontscreen section 67 includes a lower mounting flange 68 held in place by aclamp block 70 which is secured to clamp block 60 by means of fasteners71. As is best illustrated in FIG. 6, clamp block 70 has an upwardlyopening enlarged recess 72 formed therein. The width of recess 72 isincreased as is 73 adjacent the upper end of the clamp block and seatedin area 73 is an elongated rod.

or pin 74 about which the lower portion of screen section 67 pivots withflange 68 being retained within the recess. Rod 74 is preferably weldedto the clamp block 70.

The upper end of screen 67 is provided with a mounting flange 75 whichis clamped against knife shield 34 by means of fasteners 76.

A rear screen section 77 extends between rear panel 22 and knife holdingblock 44. Screen section 77 has an upper mounting flange 78 which isclamped between an impact bar 79 and a rear material deflector 80.lmpact bar 79 is held in insulating relationship with a supp'ort bracket81 by a plurality of fasteners 82. Fasteners 82 are threaded into nutelements positioned within resilient grommets or well nuts 83 which arereceived in the mounting bracket 81 which is further secured to the rearpanel 21. Well nuts 83, in cooperation with the impact bar 79,resiliently clamp the upper end of screen segment 77 in position.Insulation of impact bar 79 from support bracket 81 is achieved as well,nuts 83 expend and form a resilient cushion as at 83a.

The lower end of screen segment 77 is provided with a mounting flange 84which is rigidly secured by means of fasteners 85 to knife holding block44.

It is noted that the openings in perforated screens segments 67 and 77are of a predetermined size for passing the granulated or comminutedplastic material.

It will be readily apparent that inasmuch as bed knife 57 and the lowerends of perforated screen segments 67 and 77 are carried by support 44,which, in turn, is resiliently mounted with respect to the housing ofgranulator 10, there is a great reduction in the transmission of noiseand impact or shock to the housing. The reduction of noise is alsogreatly facilitated by the resilient clamping of the upper end of screensection 7 7. At this time it is also particularly noted that althoughknife holding block 44 is resiliently mounted so as to abate thetransmittal of noise and impact or shock, block 44, for all practicalpurposes, is supported so that there is no undue movement of the bedknife 57.

With respect to FIG. 4, rear material deflector 80 has already beenreferred to. The material deflector 80 directs falling material downonto rear screen segment 77 and into position for movement by rotatingknives 30 into cooperation with bed knife 57. The granulated particles,when of sufficiently small size, pass through the openings in screensegment 67. Those segments which are not sufficiently small in size topass through the openings in screen segments 67 are engaged between therotating knives 30 and bed knife 33 and further comminution thereof iseffected.

It is to be noted that rotor 27, by being hollow, also admits materialsto be granulated down into the area of front screen section 67 forgranulation by the cooperation of rotating knives 30 and bed knife 33.Further, it is to be noted that the shape of support 32 is such thatparticles to be granulated fall down into the center area of rotor 27for transmission therethrough. The granulated particles passing throughscreen segments 67, 77 fall into the lower portion of housing 50 and arecollected in a tray 87 removably mounted therein.

Rotor 27 is driven by an electric motor 88 which is seated on base 11 tothe rear of housing 15. Motor 88 includes a shaft 90 having a drivingsheave 91 thereon. Suitable drive belts 92 couple the sheaves 91 and 28to effectively drive rotor 27.

Sheaves 28, 91, as well as the drive belts 92, are disposed within asuitable guard 93 which is secured to the side panel 17 and base 11 soas to meet all safety requirements. Guard 93 is readily removable forinspection and belt replacement purposes.

The upper end of housing 15 is open and has seated thereon a horizontalfeed hopper, generally identified by the numeral 94. Hopper 94 isgenerally rectangular in cross-section and is in communication with theinterior of housing 15 through an opening (not shown) in a bottom wall95 thereof. Hopper 94 is provided with a sloping rear wall 96. As isbest shown in FIG. 1, an access opening 97 is provided at the front endthrough which materials, such as plastic materials, to be granulated arefed. At this time it is particularly noted that the distance from accessopening 97 to the path of rotating rotor 27 and knives 30 carriedthereby is in excess of the reach of a person; and, therefore, it isphysically impossible for an operator of the granulator to reach intothe housing 15 and to come into contact with the rotating blades 30.

With more particular attention now to feed hopper 94, said feed hopperis provided with a removable draw-type inner muffler liner assembly 98from which are suspended baffles 100a and 1110b. Baffle 100a extendsinto the interior of housing 15 (FIG. 2) and acts to prevent granulatedparticles deflected off rear panel 21 from ricocheting out throughopening 97. Muffler liner assembly 98 serves to attenuate noise thatwould otherwise escape through the feed opening while lending itself tothorough cleaning by virtue of its being slidable out of hopper 94.;

It is noted that, as shown in FIG. 2, the feed hopper 94 is removablymounted on the housing 15 in a suitable manner including brackets 10 1extending along opposite sides of the housing 15. When feed hopper 94 isremoved from housing 15, it will be readily apparent that access torotating rotor 27 and blades 30 carried thereby is possible. Therefore,it is desired to render drive motor 88 inoperative when feed hopper 94is removed. To this end there is mounted on one of the side plates,namely side plate 16, a safety switch 102. Said safety switch 102 iselectrically connected in the circuit for motor 88 and includes an.upstanding plunger 103 which bears against feed hopper 94. When feedhopper 94 is removed, plunger 103 moves upwardly and opens switch 102,thereby de-energiizing motor 88.

As seen in FIGS. 1 and 3 front panel 20 has a small plate 104 securedthereto adjacent one edge thereof 1 with plate 104 projecting beyond theedge of front panel 20. Plate 104 is associated with another plunger 105of switch 102 so that when front panel 20 is removed, switch 102 willopen and electric motor 88 deenergized so that rotor 27 cannot be drivenwhile access to the interior of the housing 15 is possible.

Rear panel 21 is provided with a similar plate 106, with plate 106engaging a third plunger 107 of switch 102. When the fasteners 22holding the rear panel in place are removed and rear panel 21 isdisplaced, plunger 107 will retract and switch 102 will open.

If it is so desired, a suitable guard 108 may be provided for theplungers 105 and 107 so as to prevent tampering.

In order to facilitate the removal of the front panel 20, the same isprovided with a pair of handles 110, as is best shown in FIGS. 1 and 2.

In a like manner, rear panel 21 is provided with a pair of handles 111.Similarly, muffler liner assembly 98 within the feed hopper 94 isprovided with a pair of handles 112. The handles 110, 111, and 112constitute safety features which prevent injury to an operator byfacilitating the handling of the removable components.

From the foregoing, it will be readily apparent that there has beendevised a granulator wherein the usual attendant noise has been greatlyreduced without requiring a special casing. At the same time, theconstructional details of the granulator are such that it is impossiblefor an operator thereof to come into contact with rotating rotor 27 andthe blades carried thereby under all possible conditions of operation ofthe granulator. It will also be readily apparent that knife holdingblock 32 could be similar supported as has been described for block 44,if desired.

Although only a preferred embodiment of the granulator has beenspecifically described herein, it is to be understood that minorvariations may be made in the granulator construction and the detailsthereof departing from the stated scope of the invention, as defined bythe appended claims.

What is claimed is:

1. Apparatus for comminuting plastics and like materials wherein saidmechanism includes a rotating cutter element and a cooperating frxedcutter element, the combination comprising, mounting means for mountingsaid fixed cutter element, fixed support means for holding said mountingmeans, said mounting means being movable in said support means in afirst direction corresponding generally to the direction of rotation ofsaid cutter element and in a second direction generally perpendicular tosaid first direction, and resilient means interposed between saidsupport means and said mounting means and operable to insulate saidmounting means from said support means while affording limited movementof said mounting means in said first and second directions.

2. Apparatus as set forth in claim 1 wherein said mounting meansincludes a cutter mounting support and clamp means for securing saidfixed cutter element to said mounting support.

3. Apparatus as set forth in claim 1 wherein said fixed support means isof a channel cross-section including a base and legs, and said mountingmeans includes a portion engaged by said legs.

8 4. Apparatus as set forth in claim 3 wherein said fixed support meansand said mounting means have opposed surfaces remote from said baselimiting movement of said mounting support away from said base.

5. Apparatus as set forth in claim 1 wherein a sectional screen ispositioned generally around the path of said rotating cutter element andgenerally along a path 7 leading into said rotating cutter element path.

6. Apparatus as set forth in claim 5 wherein said screen has oppositepositioning edges, and at least one of said edges is supported oninsulated support means.

7. Apparatus as set forth in claim 6 wherein said insulated supportmeans includes a fixed bracket, a plurality of insulated supportelements carried by said fixed bracket, and fasteners securing said oneedge to said fixed bracket through said insulated support elements.

1. Apparatus for comminuting plastics and like materials wherein saidmechanism includes a rotating cutter element and a cooperating fixedcutter element, the combination comprising, mounting means for mountingsaid fixed cutter element, fixed support means for holding said mountingmeans, said mounting means being movable in said support means in afirst direction corresponding generally to the direction of rotation ofsaid cutter element and in a second direction generally perpendicular tosaid first direction, and resilient means interposed between saidsupport means and said mounting means and operable to insulate saidmounting means from said support means while affording limited movementof said mounting means in said first and second directions.
 2. Apparatusas set forth in claim 1 wherein said mounting means includes a cuttermounting support and clamp means for securing said fixed cutter elementto said mounting support.
 3. Apparatus as set forth in claim 1 whereinsaid fixed support means is of a channel cross-section including a baseand legs, and said mounting means includes a portion engaged by saidlegs.
 4. Apparatus as set forth in claim 3 wherein said fixed supportmeans and said mounting means have opposed surfaces remote from saidbase limiting movement of said mounting support away from said base. 5.Apparatus as set forth in claim 1 wherein a sectional screen ispositioned generally around the path of said rotating cutter element andgenerally along a path leading into said rotating cutter element path.6. Apparatus as set forth in claim 5 wherein said screen has oppositepositioning edges, and at least one of said edges is supported oninsulated support means.
 7. Apparatus as set forth in claim 6 whereinsaid insulated support means includes a fixed bracket, a plurality ofinsulated supporT elements carried by said fixed bracket, and fastenerssecuring said one edge to said fixed bracket through said insulatedsupport elements.